Fatal error: Cannot redeclare mysql2date

Hello everyone ,

when i try to go on my website my-esource.com , i get this error message ( Fatal error: Cannot redeclare mysql2date() (previously declared in /home/nmmarwan/public_html/wp-includes/functions.php:26) in /home/nmmarwan/public_html/wp-content/themes/dt-the7/functions.php on line 42 ).

I really don’t know what to do .

These are the lines 26 to 42 quoted in the error message :

function mysql2date( $format, $date, $translate = true ) {
	if ( empty( $date ) )
		return false;

	if ( 'G' == $format )
		return strtotime( $date . ' +0000' );

	$i = strtotime( $date );

	if ( 'U' == $format )
		return $i;

	if ( $translate )
		return date_i18n( $format, $i );
	else
		return date( $format, $i );
}

Thank you